Fluid polyester molding masses

ABSTRACT

Thermoplastic molding compositions comprising
     A) from 10 to 99.99% by weight of at least one thermoplastic polyester   B) from 0.01 to 50% by weight of a highly branched or hyperbranched polyester of A x B y  type where x is at least 1.1 and y is at least 2.1   C) from 0 to 60% by weight of other additives,
 
where the total of the percentages by weight of components A) to C) is 100%.

This application is the National Stage of International Application No.PCT/EP2005/001015 filed on Feb. 2, 2005; and this application claimspriority of Application No. 102004005657.9 filed in Germany on Feb. 4,2004 under 35 U.S.C. §119; the entire contents of all are herebyincorporated by reference.

The invention relates to thermoplastic molding compositions comprising

-   A) from 10 to 99.99% by weight of at least one thermoplastic    polyester-   B) from 0.01 to 50% by weight of a highly branched or hyperbranched    polyester of A_(x)B_(y) type where x is at least 1.1 and y is at    least 2.1-   C) from 0 to 60% by weight of other additives,

where the total of the percentages by weight of components A) to C) is100%.

The invention further relates to the use of the inventive moldingcompositions for producing fibers, films, or moldings of any type, andalso to the moldings thus obtainable.

To improve flowability, low-molecular-weight additives are usually addedto semicrystalline thermoplastics. However, the action of theseadditives is subject to severe restriction, because, for example, thefall-off in mechanical properties becomes unacceptable when the amountadded of the additive exceeds a certain level.

Dendritic polymers with a perfectly symmetrical structure, referred toas dendrimers, can be prepared starting from a central molecule bycontrolled stepwise linking, two or more at a time, of difunctional orhigher polyfunctional monomers to each monomer already bonded. With eachlinking step there is exponential growth in the number of monomer endgroups (and hence of linkages), and polymers are obtained which havetreelike structures, ideally spherical, whose branches each containexactly the same number of monomer units. On the basis of this perfectstructure the polymer properties are advantageous; for example, asurprisingly low viscosity is observed, and also a high reactivity,owing to the high number of functional groups on the surface of thesphere. The preparation, however, is complicated by the fact that ateach linking step it is necessary to introduce protective groups andremove them again, and purifying operations are necessary, which is whydendrimers are normally prepared only on a laboratory scale.

With industrial processes it is possible, however, to prepare highlybranched or hyperbranched polymers. These polymers, in addition toperfect dendritic structures, also feature linear polymer chains andunequal polymer branches, although this does not substantially impairthe polymer properties as compared with those of the perfect dendrimers.Hyperbranched polymers can be prepared by two synthesis routes, known asAB₂ and A_(x)+B_(y). Here, A_(x) and B_(y) are different monomers andthe indices x and y are the number of functional groups present in A andB respectively, in other words the functionality of A and B. In the caseof the AB₂ route a trifunctional monomer having one reactive group A andtwo reactive groups B is converted into a highly branched orhyperbranched polymer. In the case of the A_(x)+B_(y) synthesis,depicted using the example of the A₂+B₃ synthesis, a difunctionalmonomer A₂ is reacted with a trifunctional monomer B₃. The initialproduct is a 1:1 adduct of A and B having on average one functionalgroup A and two functional groups B, and this adduct can then likewisereact to give a highly branched or hyperbranched polymer.

WO-97/45474 discloses thermoplastic compositions which comprisedendrimeric polyesters in the form of an AB₂ molecule. Here, apolyhydric alcohol as core molecule reacts with dimethylpropionic acidas AB₂ molecule to give a dendrimeric polyester. This contains only OHfunctionalities at the end of the chain. Disadvantages of these mixturesare the high glass transition temperature of the dendrimeric polyesters,the comparatively complicated preparation process, and especially thepoor solubility of the dendrimers in the polyester matrix.

According to the teaching of DE-A 101 32 928, the incorporation ofbranching agents of this type by means of compounding and solid-phasepost-condensation improves mechanical properties (molecular weightincrease). Disadvantages of the process variant described are the longpreparation time and the disadvantageous properties previouslymentioned.

The present invention was therefore based on the object of providingthermoplastic polyester molding compositions which have good flowabilitytogether with good mechanical properties.

Accordingly, the molding compositions defined at the outset have beenfound. Preferred embodiments are given in the subclaims.

The inventive molding compositions comprise, as component (A), from 10to 99.99% by weight, preferably from 30 to 99.5% by weight, and inparticular from 30 to 99.3% by weight, of at least one thermoplasticpolyester other than B).

Use is generally made of polyesters A) based on aromatic dicarboxylicacids and on an aliphatic or aromatic dihydroxy compound.

A first group of preferred polyesters is that of polyalkyleneterephthalates, in particular those having from 2 to 10 carbon atoms inthe alcohol moiety.

Polyalkylene terephthalates of this type are known per se and aredescribed in the literature. Their main chain contains an aromatic ringwhich derives from the aromatic dicarboxylic acid. There may also besubstitution in the aromatic ring, e.g. by halogen, such as chlorine orbromine, or by C₁-C₄-alkyl, such as methyl, ethyl, iso- or n-propyl, orn-, iso- or tert-butyl.

These polyalkylene terephthalates may be prepared by reacting aromaticdicarboxylic acids, or their esters or other ester-forming derivatives,with aliphatic dihydroxy compounds in a manner known per se.

Preferred dicarboxylic acids are 2,6-naphthalenedicarboxylic acid,terephthalic acid and isophthalic acid, and mixtures of these. Up to 30mol %, preferably not more than 10 mol %, of the aromatic dicarboxylicacids may be replaced by aliphatic or cycloaliphatic dicarboxylic acids,such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids andcyclohexanedicarboxylic acids.

Preferred aliphatic dihydroxy compounds are diols having from 2 to 6carbon atoms, in particular 1,2-ethanediol, 1,3-propanediol,1,4-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-cyclohexanediol,1,4-cyclohexanedimethanol and neopentyl glycol, and mixtures of these.

Particularly preferred polyesters (A) are polyalkylene terephthalatesderived from alkanediols having from 2 to 6 carbon atoms. Among these,particular preference is given to polyethylene terephthalate,polypropylene terephthalate and polybutylene terephthalate, and mixturesof these. Preference is also given to PET and/or PBT which comprise, asother monomer units, up to 1% by weight, preferably up to 0.75% byweight, of 1,6-hexanediol and/or 2-methyl-1,5-pentanediol. The viscositynumber of the polyesters (A) is generally in the range from 50 to 220,preferably from 80 to 160 (measured in 0.5% strength by weight solutionin a phenol/o-dichlorobenzene mixture in a weight ratio of 1:1 at 25°C.) in accordance with ISO 1628.

Particular preference is given to polyesters whose carboxyl end groupcontent is up to 100 mval/kg of polyester, preferably up to 50 mval/kgof polyester and in particular up to 40 mval/kg of polyester. Polyestersof this type may be prepared, for example, by the process of DE-A 44 01055. The carboxyl end group content is usually determined by titrationmethods (e.g. potentiometry).

Particularly preferred molding compositions comprise, as component A), amixture of polyesters other than PBT, for example polyethyleneterephthalate (PET). The proportion of the polyethylene terephthalate,for example, in the mixture is preferably up to 50% by weight, inparticular from 10 to 35% by weight, based on 100% by weight of A).

It is also advantageous to use recycled PET materials (also termed scrapPET) if appropriate mixed with polyalkylene terephthalates, such as PBT.

Recycled materials are generally:

-   1) those known as post-industrial recycled materials: these are    production wastes during polycondensation or during processing, e.g.    sprues from injection molding, start-up material from injection    molding or extrusion, or edge trims from extruded sheets or films.-   2) post-consumer recycled materials: these are plastic items which    are collected and treated after utilization by the end consumer.    Blow-molded PET bottles for mineral water, soft drinks and juices    are easily the predominant items in terms of quantity.

Both types of recycled material may be used either as ground material orin the form of pellets. In the latter case, the crude recycled materialsare separated and purified and then melted and pelletized using anextruder. This usually facilitates handling and free flow, and meteringfor further steps in processing.

The recycled materials used may either be pelletized or in the form ofregrind. The edge length should not be more than 10 mm, preferably lessthan 8 mm.

Because polyesters undergo hydrolytic cleavage during processing (due totraces of moisture) it is advisable to predry the recycled material. Theresidual moisture content after drying is preferably <0.2%, inparticular <0.05%.

Another group to be mentioned is that of fully aromatic polyestersderiving from aromatic dicarboxylic acids and aromatic dihydroxycompounds.

Suitable aromatic dicarboxylic acids are the compounds previouslymentioned for the polyalkylene terephthalates. The mixtures preferablyused are made from 5 to 100 mol % of isophthalic acid and from 0 to 95mol % of terephthalic acid, in particular from about 50 to about 80% ofterephthalic acid and from 20 to about 50% of isophthalic acid.

The aromatic dihydroxy compounds preferably have the formula

where Z is alkylene or cycloalkylene having up to 8 carbon atoms,arylene having up to 12 carbon atoms, carbonyl, sulfonyl, oxygen orsulfur, or a chemical bond, and m is from 0 to 2. The phenylene groupsof the compounds may also have substitution by C₁-C₆-alkyl or alkoxy andfluorine, chlorine or bromine.

Examples of parent compounds for these compounds are

dihydroxybiphenyl,

di(hydroxyphenyl)alkane,

di(hydroxyphenyl)cycloalkane,

di(hydroxyphenyl) sulfide,

di(hydroxyphenyl) ether,

di(hydroxyphenyl) ketone,

di(hydroxyphenyl) sulfoxide,

α,α′-di(hydroxyphenyl)dialkylbenzene,

di(hydroxyphenyl) sulfone, di(hydroxybenzoyl)benzene,

resorcinol, and

hydroquinone, and also the ring-alkylated and ring-halogenatedderivatives of these.

Among these, preference is given to

4,4′-dihydroxybiphenyl,

2,4-di(4′-hydroxyphenyl)2-methylbutane,

α,α′-di(4-hydroxyphenyl)-p-diisopropylbenzene,

2,2-di(3′-methyl-4′-hydroxyphenyl)propane, and

2,2-di(3′-chloro-4′-hydroxyphenyl)propane,

and in particular to

2,2-di(4′-hydroxyphenyl)propane

2,2-di(3′,5-dichlorodihydroxyphenyl)propane,

1,1-di(4′-hydroxyphenyl)cyclohexane,

3,4′-dihydroxybenzophenone,

4,4′-dihydroxydiphenyl sulfone and

2,2-di(3′,5′-dimethyl-4′-hydroxyphenyl)propane

and mixtures of these.

It is, of course, also possible to use mixtures of polyalkyleneterephthalates and fully aromatic polyesters. These generally comprisefrom 20 to 98% by weight of the polyalkylene terephthalate and from 2 to80% by weight of the fully aromatic polyester.

It is, of course, also possible to use polyester block copolymers, suchas copolyether-esters. Products of this type are known per se and aredescribed in the literature, e.g. in U.S. Pat. No. 3,651,014.Corresponding products are also available commercially, e.g. Hytrel®(DuPont).

According to the invention, polyesters include halogen-freepolycarbonates. Examples of suitable halogen-free polycarbonates arethose based on diphenols of the formula

where Q is a single bond, C₁-C₈-alkylene, C₂-C₃-alkylidene,C₃-C₆-cycloalkylidene, C₆-C₁₂arylene, or —O—, —S— or —SO₂—, and m is awhole number from 0 to 2.

The phenylene radicals of the diphenols may also have substituents, suchas C₁-C₆-alkyl or C₁-C₆-alkoxy.

Examples of preferred diphenols of the formula are hydroquinone,resorcinol, 4,4′-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane,2,4-bis(4-hydroxyphenyl)-2-methylbutane and1,1-bis(4-hydroxyphenyl)cyclohexane. Particular preference is given to2,2-bis(4-hydroxyphenyl)propane and 1,1-bis(4-hydroxyphenyl)cyclohexane,and also to 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.

Either homopolycarbonates or copolycarbonates are suitable as componentA, and preference is given to the copolycarbonates of bisphenol A, aswell as to bisphenol A homopolymer.

Suitable polycarbonates may be branched in a known manner, specificallyby incorporating 0.05 to 2.0 mol %, based on the total of the biphenolsused, of at least trifunctional compounds, for example those havingthree or more phenolic OH groups.

Polycarbonates which have proven particularly suitable have relativeviscosities n_(rel) of from 1.10 to 1.50, in particular from 1.25 to1.40. This corresponds to an average molar mass M_(w) (weight-average)of from 10 000 to 200 000 g/mol, preferably from 20 000 to 80 000 g/mol.

The diphenols of the formula are known per se or can be prepared byknown processes.

The polycarbonates may, for example, be prepared by reacting thediphenols with phosgene in the interfacial process, or with phosgene inthe homogeneous-phase process (known as the pyridine process), and ineach case the desired molecular weight may be achieved in a known mannerby using an appropriate amount of known chain terminators. (In relationto polydiorganosiloxane-containing polycarbonates see, for example, DE-A33 34 782).

Examples of suitable chain terminators are phenol, p-tert-butylphenol,or else long-chain alkylphenols, such as 4-(1,3-tetramethylbutyl)phenolas in DE-A 28 42 005, or monoalkylphenols, or dialkylphenols with atotal of from 8 to 20 carbon atoms in the alkyl substituents as inDE-A-35 06 472, such as p-nonylphenyl, 3,5-di-tert-butylphenol,p-tert-octylphenol, p-dodecylphenol, 2-(3,5-dimethylheptyl)phenol and4-(3,5-dimethylheptyl)phenol.

For the purposes of the present invention, halogen-free polycarbonatesare polycarbonates made from halogen-free biphenols, from halogen-freechain terminators and, if used, halogen-free branching agents, where thecontent of subordinate amounts at the ppm level of hydrolyzablechlorine, resulting, for example, from the preparation of thepolycarbonates with phosgene in the interfacial process, is not regardedas meriting the term halogen-containing for the purposes of theinvention. Polycarbonates of this type with contents of hydrolyzablechlorine at the ppm level are halogen-free polycarbonates for thepurposes of the present invention.

Other suitable components A) which may be mentioned are amorphouspolyester carbonates, where during the preparation process phosgene hasbeen replaced by aromatic dicarboxylic acid units, such as isophthalicacid and/or terephthalic acid units. Reference may be made at this pointto EP-A 711 810 for further details.

EP-A 365 916 describes other suitable copolycarbonates having cycloalkylradicals as monomer units.

It is also possible for bisphenol A to be replaced by bisphenol TMC.Polycarbonates of this type are obtainable from Bayer with the trademarkAPEC HT®.

The inventive molding compositions comprise, as component B), from 0.01to 50% by weight, preferably from 0.5 to 20% by weight, and inparticular from 0.7 to 10% by weight, of a hyperbranched polyester ofA_(x)B_(y) type, where

-   x is at least 1.1, preferably at least 1.3, in particular at least 2-   y is at least 2.1, preferably at least 2.5, in particular at least    3.

Use may also be made of mixtures as units A and/or B, of course.

An A_(x)B_(y)-type polyester is a condensate composed of an x-functionalmolecule A and a y-functional molecule B. By way of example, mention maybe made of a polyester composed of adipic acid as molecule A (x=2) andglycerol as molecule B (y=3). For the purposes of this invention,hyperbranched polyesters are non-crosslinked macromolecules havinghydroxy groups and carboxy groups, these having both structural andmolecular non-uniformity. Their structure may firstly be based on acentral molecule in the same way as dendrimers, but with non-uniformchain length of the branches. Secondly, they may also have a linearstructure with functional pendant groups, or else they combine the twoextremes, having linear and branched molecular portions. See also P. J.Flory, J. Am. Chem. Soc. 1952, 74, 2718, and H. Frey et al., Chem. Eur.J. 2000, 6, No.14, 2499 for the definition of dendrimeric andhyperbranched polymers.

“Hyperbranched” in the context of the present invention means that thedegree of branching (DB), i.e. the average number of dendritic linkagesplus the average number of end groups per molecule, is from 10 to 99.9%,preferably from 20 to 99%, particularly preferably from 20 to 95%.

“Dendrimer” in the context of the present invention means that thedegree of branching is from 99.9 to 100%. See H. Frey et al., ActaPolym. 1997, 48, 30 for the definition of “degree of branching”.

The degree of branching (DB) of the compounds in question is defined as

${{DB} = {\frac{T + Z}{T + Z + L} \times 100\%}},$

(where T is the average number of terminal monomer units, Z the averagenumber of branched monomer units and L the average number of linearmonomer units in the macromolecules of the respective compounds).

Component B) preferably has an M_(n) of from 300 to 30 000 g/mol, inparticular from 400 to 25 000 g/mol, and very particularly from 500 to20 000 g/mol, determined by means of GPC, PMMA standard,dimethylacetamide eluent.

B) preferably has an OH number of from 0 to 600 mg KOH/g of polyester,preferably of from 1 to 500 mg KOH/g of polyester, in particular from 20to 500 mg KOH/g of polyester to DIN 53240, and preferably a COOH numberof from 0 to 600 mg KOH/g of polyester, preferably from 1 to 500 mgKOH/g of polyester, and in particular from 2 to 500 mg KOH/g ofpolyester.

The T_(g) is preferably from −50° C. to 140° C., and in particular from−50 to 100° C. (by means of DSC, to DIN 53765).

Preference is particularly given to those components B) in which atleast one OH or COOH number is greater than 0, preferably greater than0.1, and in particular greater than 0.5.

The inventive component B) is in particular obtainable via the processesdescribed below, namely by reacting

-   (a) one or more dicarboxylic acids or one or more derivatives of the    same with one or more at least trihydric alcohols    or-   (b) one or more tricarboxylic acids or higher polycarboxylic acids    or one or more derivatives of the same with one or more diols

in the presence of a solvent and optionally in the presence of aninorganic, organometallic, or low-molecular-weight organic catalyst, orof an enzyme. The reaction in solvent is the preferred preparationmethod.

For the purposes of the present invention, highly functionalhyperbranched polyesters have molecular and structural non-uniformity.Their molecular non-uniformity distinguishes them from dendrimers, andthey can therefore be prepared at considerably lower cost.

Among the dicarboxylic acids which can be reacted according to variant(a) are, by way of example, oxalic acid, malonic acid, succinic acid,glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid,sebacic acid, undecane-α,ω-dicarboxylic acid, dodecane-α,ω-dicarboxylicacid, cis- and trans-cyclohexane-1,2-dicarboxylic acid, cis- andtrans-cyclohexane-1,3-dicarboxylic acid, cis- andtrans-cyclohexane-1,4-dicarboxylic acid, cis- andtrans-cyclopentane-1,2-dicarboxylic acid, and cis- andtrans-cyclopentane-1,3-dicarboxylic acid,

and the abovementioned dicarboxylic acids may have substitution by oneor more radicals selected from

C₁-C₁₀-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl, n-octyl, 2-ethylhexyl, n-nonyl, andn-decyl,

C₃-C₁₂-cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl and cyclododecyl; preference is given to cyclopentyl,cyclohexyl, and cycloheptyl;

alkylene groups, such as methylene or ethylidene, or

C₆-C₁₄-aryl groups, such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,4-phenanthryl, and 9-phenanthryl, preferably phenyl, 1-naphthyl, and2-naphthyl, particularly preferably phenyl.

Examples which may be mentioned of representatives of substituteddicarboxylic acids are: 2-methylmalonic acid, 2-ethylmalonic acid,2-phenylmalonic acid, 2-methylsuccinic acid, 2-ethylsuccinic acid,2-phenylsuccinic acid, itaconic acid, 3,3-dimethylglutaric acid.

Among the dicarboxylic acids which may be reacted according to variant(a) are also ethylenically unsaturated acids, such as maleic acid andfumaric acid, and aromatic dicarboxylic acids, such as phthalic acid,isophthalic acid or terephthalic acid.

It is also possible to use mixtures of two or more of the abovementionedrepresentative compounds.

The dicarboxylic acids may either be used as they stand or be used inthe form of derivatives.

Derivatives are preferably

-   -   the relevant anhydrides in monomeric or else polymeric form,    -   mono- or dialkyl esters, preferably mono- or dimethyl esters, or        the corresponding mono- or diethyl esters, or else the mono- and        dialkyl esters derived from higher alcohols, such as n-propanol,        isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol,        n-hexanol,    -   and also mono- and divinyl esters, and    -   mixed esters, preferably methyl ethyl esters.

In the preferred preparation process it is also possible to use amixture composed of a dicarboxylic acid and one or more of itsderivatives. Equally, it is possible to use a mixture of two or moredifferent derivatives of one or more dicarboxylic acids.

It is particularly preferable to use succinic acid, glutaric acid,adipic acid, phthalic acid, isophthalic acid, terephthalic acid, or themono- or dimethyl ester thereof. It is very particularly preferable touse adipic acid.

Examples of at least trihydric alcohols which may be reacted are:glycerol, butane-1,2,4-triol, n-pentane-1,2,5-triol,n-pentane-1,3,5-triol, n-hexane-1,2,6-triol, n-hexane-1,2,5-triol,n-hexane-1,3,6-triol, trimethylolbutane, trimethylolpropane orditrimethylolpropane, trimethylolethane, pentaerythritol ordipentaerythritol; sugar alcohols, such as mesoerythritol, threitol,sorbitol, mannitol, or mixtures of the above at least trihydricalcohols. It is preferable to use glycerol, trimethylolpropane,trimethylolethane, and pentaerythritol.

Examples of tricarboxylic acids or polycarboxylic acids which may bereacted according to variant (b) are benzene-1,2,4-tricarboxylic acid,benzene-1,3,5-tricarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid,and mellitic acid.

Tricarboxylic acids or polycarboxylic acids may be used in the inventivereaction either as they stand or else in the form of derivatives.

Derivatives are preferably

-   -   the relevant anhydrides in monomeric or else polymeric form,    -   mono-, di-, or trialkyl esters, preferably mono-, di-, or        trimethyl esters, or the corresponding mono-, di-, or triethyl        esters, or else the mono-, di-, and triesters derived from        higher alcohols, such as n-propanol, isopropanol, n-butanol,        isobutanol, tert-butanol, n-pentanol, n-hexanol, or else mono-,        di-, or trivinyl esters    -   and mixed methyl ethyl esters.

For the purposes of the present invention, it is also possible to use amixture composed of a tri- or polycarboxylic acid and one or more of itsderivatives. For the purposes of the present invention it is likewisepossible to use a mixture of two or more different derivatives of one ormore tri- or polycarboxylic acids, in order to obtain component B).Examples of diols used for variant (b) of the present invention areethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,2-diol,butane-1,3-diol, butane-1,4-diol, butane-2,3-diol, pentane-1,2-diol,pentane-1,3-diol, pentane-1,4-diol, pentane-1,5-diol, pentane-2,3-diol,pentane-2,4-diol, hexane-1,2-diol, hexane-1,3-diol, hexane-1,4-diol,hexane-1,5-diol, hexane-1,6-diol, hexane-2,5-diol, heptan-1,2-diol,1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol,1,10-decanediol, 1,2-decanediol, 1,12-dodecanediol, 1,2-dodecanediol,1,5-hexadiene-3,4-diol, cyclopentanediols, cyclohexanediols, inositoland derivatives, (2)-methylpentane-2,4-diol,2,4-dimethylpentane-2,4-diol, 2-ethylhexane-1,3-diol,2,5-dimethylhexane-2,5-diol, 2,2,4-trimethylpentane-1,3-diol, pinacol,diethylene glycol, triethylene glycol, dipropylene glycol, tripropyleneglycol, polyethylene glycols HO(CH₂CH₂O)_(n)—H or polypropylene glycolsHO(CH[CH₃]CH₂O)_(n)—H or mixtures of two or more representativecompounds of the above compounds, where n is a whole number and n=4 to25. One, or else both, hydroxy groups here in the abovementioned diolsmay also be substituted by SH groups. Preference is given to ethyleneglycol, propane-1,2-diol, and diethylene glycol, triethylene glycol,dipropylene glycol, and tripropylene glycol.

The molar ratio of the molecules A to molecules B in the A_(x)B_(y)polyester in the variants (a) and (b) is from 4:1 to 1:4, in particularfrom 2:1 to 1:2.

The at least trihydric alcohols reacted according to variant (a) of theprocess may have hydroxy groups all of which have identical reactivity.Preference is also given here to at least trihydric alcohols whose OHgroups initially have identical reactivity, but where reaction with atleast one acid group can induce a fall-off in reactivity of theremaining OH groups as a result of steric or electronic effects. By wayof example, this applies when trimethylolpropane or pentaerythritol isused.

However, the at least trihydric alcohols reacted according to variant(a) may also have hydroxy groups having at least two different chemicalreactivities.

The different reactivity of the functional groups here may either derivefrom chemical causes (e.g. primary/secondary/tertiary OH group) or onsteric causes.

By way of example, the triol may comprise a triol which has primary andsecondary hydroxy groups, preferred example being glycerol.

When the inventive reaction is carried out according to variant (a), itis possible to use triol or mixtures of triols which contain up to 50mol % (based on the polyol mixture) of difunctional alcohols, althoughit is preferred to operate in the absence of diols and monofunctionalalcohols.

When the inventive reaction is carried out according to variant (b), itis possible to use the tricarboxylic acids or mixtures thereof, whichmay contain up to 50 mol %, based on the acid mixture, of difunctionalcarboxylic acids, although it is preferred to operate in the absence ofmono- or dicarboxylic acids.

The inventive process is preferably carried out in the presence of asolvent. Examples of suitable compounds are hydrocarbons, such asparaffins or aromatics. Particularly suitable paraffins are n-heptaneand cyclohexane. Particularly suitable aromatics are toluene,ortho-xylene, meta-xylene, para-xylene, xylene in the form of an isomermixture, ethylbenzene, chlorobenzene and ortho- andmeta-dichlorobenzene. Other very particularly suitable solvents in theabsence of acidic catalysts are: ethers, such as dioxane ortetrahydrofuran, and ketones, such as methyl ethyl ketone and methylisobutyl ketone.

According to the invention, the amount of solvent added is at least 0.1%by weight, based on the weight of the starting materials used and to bereacted, preferably at least 1% by weight, and particularly preferablyat least 10% by weight. It is also possible to use excesses of solvent,based on the weight of starting materials used and to be reacted, e.g.from 1.01 to 10 times the amount. Solvent amounts of more than 100 timesthe weight of the starting materials used and to be reacted are notadvantageous, because the reaction rate reduces markedly at markedlylower concentrations of the reactants, giving uneconomically longreaction times.

To carry out the process preferred according to the invention,operations may be carried out in the presence of a dehydrating agent asadditive, added at the start of the reaction. Suitable examples aremolecular sieves, in particular 4 Å molecular sieve, MgSO₄, and Na₂SO₄.During the reaction it is also possible to add further dehydrating agentor to replace dehydrating agent by fresh dehydrating agent. During thereaction it is also possible to remove the water or alcohol formed bydistillation and, for example, to use a water separator.

The reaction may be carried out in the absence of acidic catalysts. Itis preferable to operate in the presence of an acidic inorganic,organometallic, or organic catalyst, or a mixture composed of two ormore acidic inorganic, organometallic, or organic catalysts.

For the purposes of the present invention, examples of acidic inorganiccatalysts are sulfuric acid, phosphoric acid, phosphonic acid,hypophosphorous acid, aluminum sulfate hydrate, alum, acidic silica gel(pH=6, in particular=5), and acidic aluminum oxide. Examples of othercompounds which may be used as acidic inorganic catalysts are aluminumcompounds of the general formula Al(OR)₃ and titanates of the generalformula Ti(OR)₄, where each of the radicals R may be identical ordifferent and is selected independently of the others from

C₁-C₁₀-alkyl radicals, such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl, n-octyl, 2-ethylhexyl, n-nonyl, andn-decyl,

C₃-C₁₂-cycloalkyl radicals, such as cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl,cyclodecyl, cycloundecyl, and cyclododecyl; preference is given tocyclopentyl, cyclohexyl, and cycloheptyl.

Each of the radicals R in Al(OR)₃ or Ti(OR)₄ is preferably identical andselected from isopropyl or 2-ethylhexyl.

Examples of preferred acidic organometallic catalysts are selected fromdialkyltin oxides R₂SnO, where R is defined as above. A particularlypreferred representative compound for acidic organometallic catalysts isdi-n-butyltin oxide, which is commercially available as “oxo-tin”, ordi-n-butyltin dilaurate.

Preferred acidic organic catalysts are organic compounds having, by wayof example, phosphate groups, sulfonic acid groups, sulfate groups, orphosphonic acid groups. Particular preference is given to sulfonicacids, such as para-toluenesulfonic acid. Acidic ion exchangers may alsobe used as acid organic catalysts, e.g. polystyrene resins containingsulfonic acid groups and crosslinked with about 2 mol % ofdivinylbenzene.

It is also possible to use combinations of two or more of theabovementioned catalysts. It is also possible to use an immobilized formof those organic or organometallic, or else inorganic catalysts whichtake the form of discrete molecules.

If the intention is to use acidic inorganic, organometallic, or organiccatalysts, according to the invention the amount used is from 0.1 to 10%by weight, preferably from 0.2 to 2% by weight, of catalyst.

The inventive process is carried out under inert gas, e.g. under carbondioxide, nitrogen, or a noble gas, among which mention may particularlybe made of argon.

The inventive process is carried out at temperatures of from 60 to 200°C. It is preferable to operate at temperatures of from 130 to 180° C.,in particular up to 150° C., or below that temperature. Maximumtemperatures up to 145° C. are particularly preferred, and temperaturesup to 135° C. are very particularly preferred.

The pressure conditions for the inventive process are not critical perse. It is possible to operate at markedly reduced pressure, e.g. at from10 to 500 mbar. The inventive process may also be carried out atpressures above 500 mbar. A reaction at atmospheric pressure ispreferred for reasons of simplicity; however, conduct at slightlyincreased pressure is also possible, e.g. up to 1200 mbar. It is alsopossible to operate at markedly increased pressure, e.g. at pressures upto 10 bar. Reaction at atmospheric pressure is preferred.

The reaction time for the inventive process is usually from 10 minutesto 25 hours, preferably from. 30 minutes to 10 hours, and particularlypreferably from one to 8 hours.

Once the reaction has ended, the highly functional hyperbranchedpolyesters can easily be isolated, e.g. by removing the catalyst byfiltration and concentrating the mixture, the concentration process hereusually being carried out at reduced pressure.

Other work-up methods with good suitability are precipitation afteraddition of water, followed by washing and drying.

Component B) can also be prepared in the presence of enzymes ordecomposition products of enzymes (according to DE-A 101 63163). For thepurposes of the present invention, the term acidic organic catalystsdoes not include the dicarboxylic acids reacted according to theinvention.

It is preferable to use lipases or esterases. Lipases and esterases withgood suitability are Candida cylindracea, Candida lipolytica, Candidarugosa, Candida antarctica, Candida utilis, Chromobacterium viscosum,Geolrichum viscosum, Geotrichum candidum, Mucor javanicus, Mucor mihei,pig pancreas, pseudomonas spp., pseudomonas fluorescens, Pseudomonascepacia, Rhizopus arrhizus, Rhizopus delemar, Rhizopus niveus, Rhizopusoryzae, Aspergillus niger, Penicillium roquefortii, Penicilliumcamembertii, or esterase from Bacillus spp. and Bacillusthermoglucosidasius. Candida antarctica lipase B is particularlypreferred. The enzymes listed are commercially available, for examplefrom Novozymes Biotech Inc., Denmark.

The enzyme is preferably used in immobilized form, for example on silicagel or Lewatit®. The processes for immobilizing enzymes are known perse, e.g. from Kurt Faber, “Biotransformations in organic chemistry”, 3rdedition 1997, Springer Verlag, Chapter 3.2 “Immobilization” pp. 345-356.Immobilized enzymes are commercially available, for example fromNovozymes Biotech Inc., Denmark.

The amount of immobilized enzyme used is from 0.1 to 20% by weight, inparticular from 10 to 15% by weight, based on the total weight of thestarting materials used and to be reacted.

The inventive process is carried out at temperatures above 60° C. It ispreferable to operate at temperatures of 100° C. or below thattemperature. Preference is given to temperatures up to 80° C., veryparticular preference is given to temperatures of from 62 to 75° C., andstill more preference is given to temperatures of from 65 to 75° C.

The inventive process is carried out in the presence of a solvent.Examples of suitable compounds are hydrocarbons, such as paraffins oraromatics. Particularly suitable paraffins are n-heptane andcyclohexane. Particularly suitable aromatics are toluene, ortho-xylene,meta-xylene, para-xylene, xylene in the form of an isomer mixture,ethylbenzene, chlorobenzene and ortho- and meta-dichlorobenzene. Othervery particularly suitable solvents are: ethers, such as dioxane ortetrahydrofuran, and ketones, such as methyl ethyl ketone and methylisobutyl ketone.

The amount of solvent added is at least 5 parts by weight, based on theweight of the starting materials used and to be reacted, preferably atleast 50 parts by weight, and particularly preferably at least 100 partsby weight. Amounts of more than 10 000 parts by weight of solvent areundesirable, because the reaction rate decreases markedly at markedlylower concentrations, giving uneconomically long reaction times.

The inventive process is carried out at pressures above 500 mbar.Preference is given to the reaction at atmospheric pressure or slightlyincreased pressure, for example at up to 1200 mbar. It is also possibleto operate under markedly increased pressure, for example at pressuresup to 10 bar. The reaction at atmospheric pressure is preferred.

The reaction time for the inventive process is usually from 4 hours to 6days, preferably from 5 hours to 5 days, and particularly preferablyfrom 8 hours to 4 days.

Once the reaction has ended, the highly functional hyperbranchedpolyesters can easily be isolated, e.g. by removing the catalyst byfiltration and concentrating the mixture, the concentration process hereusually being carried out at reduced pressure. Other work-up methodswith good suitability are precipitation after addition of water,followed by washing and drying.

The present invention also provides the highly functional, hyperbranchedpolyesters obtainable by the inventive process. They have particularlylow content of discolored and resinified material. For the definition ofhyperbranched polymers, see also: P. J. Flory, J. Am. Chem. Soc. 1952,74, 2718, and A. Sunder et al., Chem. Eur. J. 2000, 6, No.1, 1-8.However, in the context of the present invention, “highly functionalhyperbranched” means that the degree of branching, i.e. the averagenumber of dendritic linkages plus the average number of end groups permolecule is from 10 to 99.9%, preferably from 20 to 99%, particularlypreferably from 30 to 90% (see in this connection H. Frey et al. ActaPolym. 1997, 48, 30).

The inventive polyesters have a molar mass M_(w) of from 500 to 50 000g/mol, preferably from 1000 to 20 000 g/mol, particularly preferablyfrom 1000 to 19 000 g/mol. The polydispersity is from 1.2 to 50,preferably from 1.4 to 40, particularly preferably from 1.5 to 30, andvery particularly preferably from 1.5 to 10. They are usually verysoluble, i.e. clear solutions can be prepared using up to 50% by weight,in some cases even up to 80% by weight, of the inventive polyesters intetrahydrofuran (THF), n-butyl acetate, ethanol, and numerous othersolvents, with no gel particles detectable by the naked eye.

The inventive highly functional hyperbranched polyesters arecarboxy-terminated, carboxy- and hydroxy-terminated, and preferablyhydroxy-terminated.

The inventive molding compositions may comprise, as component C), from 0to 60% by weight, in particular up to 50% by weight, of other additivesand processing aids, other than B).

The inventive molding compositions may comprise, as component C), from 0to 5% by weight, preferably from 0.05 to 3% by weight, and in particularfrom 0.1 to 2% by weight, of at least one ester or amide of saturated orunsaturated aliphatic carboxylic acids having from 10 to 40 carbonatoms, preferably from 16 to 22 carbon atoms, with aliphatic saturatedalcohols or amines having from 2 to 40 carbon atoms, preferably from 2to 6 carbon atoms.

The carboxylic acids may be monobasic or dibasic. Examples which may bementioned are pelargonic acid, palmitic acid, lauric acid, margaricacid, dodecanedioic acid, behenic acid, and particularly preferablystearic acid, capric acid, and also montanic acid (a mixture of fattyacids having from 30 to 40 carbon atoms).

The aliphatic alcohols may be mono- to tetrahydric. Examples of alcoholsare n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propyleneglycol, neopentyl glycol, pentaerythritol, preference being given toglycerol and pentaerythritol.

The aliphatic amines may be mono-, di- or triamines. Examples of theseare stearylamine, ethylenediamine, propylenediamine,hexamethylenediamine, di(6-aminohexyl)amine, particular preference beinggiven to ethylenediamine and hexamethylenediamine. Correspondingly,preferred esters or amides are glycerol distearate, glyceroltristearate, ethylenediamine distearate, glycerol monopalmitate,glyceryl trilaurate, glyceryl monobehenate, and pentaerythrityltetrastearate.

It is also possible to use mixtures of various esters or amides, oresters with amides combined, the mixing ratio here being as desired.

Examples of amounts of other usual additives C) are up to 40% by weight,preferably up to 30% by weight, of elastomeric polymers (also oftentermed impact modifiers, elastomers, or rubbers).

These are very generally copolymers which have preferably been built upfrom at least two of the following monomers: ethylene, propylene,butadiene, isobutene, isoprene, chloroprene, vinyl acetate, styrene,acrylonitrile and acrylates and/or methacrylates having from 1 to 18carbon atoms in the alcohol component.

Polymers of this type are described, for example, in Houben-Weyl,Methoden der organischen Chemie, Vol. 14/1 (Georg-Thieme-Verlag,Stuttgart, Germany, 1961), pages 392-406, and in the monograph by C. B.Bucknall, “Toughened Plastics” (Applied Science Publishers, London,1977).

Some preferred types of such elastomers are described below.

Preferred types of such elastomers are those known as ethylene-propylene(EPM) and ethylene-propylene-diene (EPDM) rubbers.

EPM rubbers generally have practically no residual double bonds, whereasEPDM rubbers may have from 1 to 20 double bonds per 100 carbon atoms.

Examples which may be mentioned of diene monomers for EPDM rubbers areconjugated dienes, such as isoprene and butadiene, non-conjugated dieneshaving from 5 to 25 carbon atoms, such as 1,4-pentadiene, 1,4-hexadiene,1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene and 1,4-octadiene, cyclicdienes, such as cyclopentadiene, cyclohexadienes, cyclooctadienes anddicyclopentadiene, and also alkenylnorbornenes, such as5-ethylidene-2-norbornene, 5-butylidene-2-norbornene,2-methallyl-5-norbornene and 2-isopropenyl-5-norbornene, andtricyclodienes, such as 3-methyltricyclo[5.2.1.0^(2,6)]-3,8-decadiene,and mixtures of these. Preference is given to 1,5-hexadiene,5-ethylidenenorbornene and dicyclopentadiene. The diene content of theEPDM rubbers is preferably from 0.5 to 50% by weight, in particular from1 to 8% by weight, based on the total weight of the rubber.

EPM and EPDM rubbers may preferably also have been grafted with reactivecarboxylic acids or with derivatives of these. Examples of these areacrylic acid, methacrylic acid and derivatives thereof, e.g. glycidyl(meth)acrylate, and also maleic anhydride.

Copolymers of ethylene with acrylic acid and/or methacrylic acid and/orwith the esters of these acids are another group of preferred rubbers.The rubbers may also include dicarboxylic acids, such as maleic acid andfumaric acid, or derivatives of these acids, e.g. esters and anhydrides,and/or monomers containing epoxy groups. These monomers containingdicarboxylic acid derivatives or containing epoxy groups are preferablyincorporated into the rubber by adding to the monomer mixture monomerscontaining dicarboxylic acid groups and/or epoxy groups and having theformula I, II, III or IV

where R¹ to R⁹ are hydrogen or alkyl having from 1 to 6 carbon atoms,and m is a whole number from 0 to 20, g is a whole number from 0 to 10and p is a whole number from 0 to 5.

R¹ to R⁹ are preferably hydrogen, where m is 0 or 1 and g is 1. Thecorresponding compounds are maleic acid, fumaric acid, maleic anhydride,allyl glycidyl ether and vinyl glycidyl ether.

Preferred compounds of the formulae I, II and IV are maleic acid, maleicanhydride and (meth)acrylates containing epoxy groups, such as glycidylacrylate and glycidyl methacrylate, and the esters with tertiaryalcohols, such as tert-butyl acrylate. Although the latter have no freecarboxy groups, their behavior approximates to that of the free acidsand they are therefore termed monomers with latent carboxy groups.

The copolymers are advantageously composed of from 50 to 98% by weightof ethylene, from 0.1 to 20% by weight of monomers containing epoxygroups and/or methacrylic acid and/or monomers containing anhydridegroups, the remaining amount being (meth)acrylates.

Particular preference is given to copolymers composed of

from 50 to 98% by weight, in particular from 55 to 95% by weight, ofethylene, from 0.1 to 40% by weight, in particular from 0.3 to 20% byweight, of glycidyl acrylate and/or glycidyl methacrylate, (meth)acrylicacid and/or maleic anhydride, and from 1 to 45% by weight, in particularfrom 10 to 40% by weight, of n-butyl acrylate and/or 2-ethylhexylacrylate.

Other preferred (meth)acrylates are the methyl, ethyl, propyl, isobutyland tert-butyl esters.

Besides these, comonomers which may be used are vinyl esters and vinylethers.

The ethylene copolymers described above may be prepared by processesknown per se, preferably by random copolymerization at high pressure andelevated temperature.

Appropriate processes are well known.

Other preferred elastomers are emulsion polymers whose preparation isdescribed, for example, by Blackley in the monograph “Emulsionpolymerization”. The emulsifiers and catalysts which may be used areknown per se.

In principle it is possible to use homogeneously structured elastomersor those with a shell structure. The shell-type structure is determinedby the sequence of addition of the individual monomers. The morphologyof the polymers is also affected by this sequence of addition.

Monomers which may be mentioned here, merely as examples, for thepreparation of the rubber fraction of the elastomers are acrylates, suchas n-butyl acrylate and 2-ethylhexyl acrylate, correspondingmethacrylates, butadiene and isoprene, and also mixtures of these. Thesemonomers may be copolymerized with other monomers, such as styrene,acrylonitrile, vinyl ethers and with other acrylates or methacrylates,such as methyl methacrylate, methyl acrylate, ethyl acrylate or propylacrylate.

The soft or rubber phase (with a glass transition temperature of below0° C.) of the elastomers may be the core, the outer envelope or anintermediate shell (in the case of elastomers whose structure has morethan two shells). Elastomers having more than one shell may also havemore than one shell made from a rubber phase.

If one or more hard components (with glass transition temperatures above20° C.) are involved, besides the rubber phase, in the structure of theelastomer, these are generally prepared by polymerizing, as principalmonomers, styrene, acrylonitrile, methacrylonitrile, (x-methylstyrene,p-methylstyrene, or acrylates or methacrylates, such as methyl acrylate,ethyl acrylate or methyl methacrylate. Besides these, it is alsopossible to use relatively small proportions of other comonomers.

It has proven advantageous in some cases to use emulsion polymers whichhave reactive groups at their surfaces. Examples of groups of this typeare epoxy, carboxy, latent carboxy, amino and amide groups, and alsofunctional groups which may be introduced by concomitant use of monomersof the formula

where:

-   R¹⁰ is hydrogen or C₁-C₄-alkyl,-   R¹¹ is hydrogen or C₁-C₈-alkyl or aryl, in particular phenyl,-   R¹² is hydrogen, C₁-C₁₀-alkyl, C₆-C₁₂-aryl or —OR¹³-   R¹³ is C₁-C₈-alkyl or C₆-C₁₂-aryl, if desired with substitution by    O- or N-containing groups,-   X is a chemical bond or C₁-C₁₀-alkylene or C₆-C₁₂-arylene, or-   Y is O—Z or NH—Z, and

-   Z is C₁-C₁₀-alkylene or C₆-C₁₂-arylene.

The graft monomers described in EP-A 208 187 are also suitable forintroducing reactive groups at the surface.

Other examples which may be mentioned are acrylamide, methacrylamide andsubstituted acrylates or methacrylates, such as (N-tert-butylamino)ethylmethacrylate, (N,N-dimethylamino)ethyl acrylate,(N,N-dimethylamino)methyl acrylate and (N,N-diethylamino)ethyl acrylate.

The particles of the rubber phase may also have been crosslinked.Examples of crosslinking monomers are 1,3-butadiene, divinylbenzene,diallyl phthalate and dihydrodicyclopentadienyl acrylate, and also thecompounds described in EP-A 50 265.

It is also possible to use the monomers known as graft-linking monomers,i.e. monomers having two or more polymerizable double bonds which reactat different rates during the polymerization. Preference is given to theuse of compounds of this type in which at least one reactive grouppolymerizes at about the same rate as the other monomers, while theother reactive group (or reactive groups), for example, polymerize(s)significantly more slowly. The different polymerization rates give riseto a certain proportion of unsaturated double bonds in the rubber. Ifanother phase is then grafted onto a rubber of this type, at least someof the double bonds present in the rubber react with the graft monomersto form chemical bonds, i.e. the phase grafted on has at least somedegree of chemical bonding to the graft base.

Examples of graft-linking monomers of this type are monomers containingallyl groups, in particular allyl esters of ethylenically unsaturatedcarboxylic acids, for example allyl acrylate, allyl methacrylate,diallyl maleate, diallyl fumarate and diallyl itaconate, and thecorresponding monoallyl compounds of these dicarboxylic acids. Besidesthese there is a wide variety of other suitable graft-linking monomers.For further details reference may be made here, for example, to U.S.Pat. No. 4,148,846.

The proportion of these crosslinking monomers in the impact-modifyingpolymer is generally up to 5% by weight, preferably not more than 3% byweight, based on the impact-modifying polymer.

Some preferred emulsion polymers are listed below. Mention may first bemade here of graft polymers with a core and with at least one outershell, and having the following structure:

Type Monomers for the core Monomers for the envelope I buta-1,3-diene,isoprene, styrene, acrylonitrile, methyl n-butyl acrylate, ethylhexylmethacrylate acrylate, or a mixture of these II as I, but withconcomitant as I use of crosslinking agents III as I or II n-butylacrylate, ethyl acrylate, methyl acrylate, buta-1,3-diene, isoprene,ethylhexyl acrylate IV as I or II as I or III, but with concomitant useof monomers having reactive groups, as described herein V styrene,acrylonitrile, first envelope made of monomers methyl methacrylate, or aas described under I and II for the mixture of these core, secondenvelope as described under I and IV for the envelope

These graft polymers, in particular ABS polymers and/or ASA polymers,are preferably used in amounts of up to 40% by weight for theimpact-modification of PBT, if appropriate in a mixture with up to 40%by weight of polyethylene terephthalate. Blend products of this type areobtainable with the trademark Ultradur®S (previously Ultrablend®S fromBASF AG).

Instead of graft polymers whose structure has more than one shell, it isalso possible to use homogeneous, i.e. single-shell, elastomers madefrom 1,3-butadiene, isoprene and n-butyl acrylate or from copolymers ofthese. These products, too, may be prepared by concomitant use ofcrosslinking monomers or of monomers having reactive groups.

Examples of preferred emulsion polymers are n-butylacrylate-(meth)acrylic acid copolymers, n-butyl acrylate-glycidylacrylate or n-butyl acrylate-glycidyl methacrylate copolymers, graftpolymers with an inner core made from n-butyl acrylate or based onbutadiene and with an outer envelope made from the abovementionedcopolymers, and copolymers of ethylene with comonomers which supplyreactive groups.

The elastomers described may also be prepared by other conventionalprocesses, e.g. by suspension polymerization.

Preference is also given to silicone rubbers, as described in DE-A 37 25576, EP-A 235 690, DE-A 38 00 603 and EP-A 319 290.

It is, of course, also possible to use mixtures of the types of rubberlisted above.

Fibrous or particulate fillers C) which may be mentioned are carbonfibers, glass fibers, glass beads, amorphous silica, asbestos, calciumsilicate, calcium metasilicate, magnesium carbonate, kaolin, chalk,powdered quartz, mica, barium sulfate and feldspar, used in amounts ofup to 50% by weight, in particular up to 40% by weight.

Preferred fibrous fillers which may be mentioned are carbon fibers,aramid fibers and potassium titanate fibers, and particular preferenceis given to glass fibers in the form of E glass. These may be used asrovings or in the commercially available forms of chopped glass.

Mixtures of glass fibers D) with component B) in a ratio of from 1:100to 1:2, and preferably from 1:10 to 1:3, are particularly preferred.

The fibrous fillers may have been surface-pretreated with a silanecompound to improve compatibility with the thermoplastic.

Suitable silane compounds have the formula:(X—(CH₂)_(n))_(k)—Si—(O—C_(m)H_(2m+1))_(4−k)where:

-   n is a whole number from 2 to 10, preferably 3 to 4,-   m is a whole number from 1 to 5, preferably 1 to 2, and-   k is a whole number from 1 to 3, preferably 1.

Preferred silane compounds are aminopropyltrimethoxysilane,aminobutyltrimethoxysilane, aminopropyltriethoxysilane andaminobutyltriethoxysilane, and also the corresponding silanes whichcontain a glycidyl group as substituent X.

The amounts of the silane compounds generally used for surface-coatingare from 0.05 to 5% by weight, preferably from 0.5 to 1.5% by weight andin particular from 0.8 to 1% by weight (based on C).

Acicular mineral fillers are also suitable.

For the purposes of the invention, acicular mineral fillers are mineralfillers with strongly developed acicular character. An example isacicular wollastonite. The mineral preferably has an L/D (length todiameter) ratio of from 8:1 to 35:1, preferably from 8:1 to 11:1. Themineral filler may, if desired, have been pretreated with theabovementioned silane compounds, but the pretreatment is not essential.

Other fillers which may be mentioned are kaolin, calcined kaolin,wollastonite, talc and chalk.

As component C), the thermoplastic molding compositions of the inventionmay comprise the usual processing aids, such as stabilizers, oxidationretarders, agents to counteract decomposition due to heat anddecomposition due to ultraviolet light, lubricants and mold-releaseagents, colorants, such as dyes and pigments, nucleating agents,plasticizers, etc.

Examples which may be mentioned of oxidation retarders and heatstabilizers are sterically hindered phenols and/or phosphites,hydroquinones, aromatic secondary amines, such as diphenylamines,various substituted members of these groups, and mixtures of these inconcentrations of up to 1% by weight, based on the weight of thethermoplastic molding compositions.

UV stabilizers which may be mentioned, and are generally used in amountsof up to 2% by weight, based on the molding composition, are varioussubstituted resorcinols, salicylates, benzotriazoles, and benzophenones.

Colorants which may be added are inorganic pigments, such as titaniumdioxide, ultramarine blue, iron oxide, and carbon black, and alsoorganic pigments, such as phthalocyanines, quinacridones and perylenes,and also dyes, such as nigrosine and anthraquinones.

Nucleating agents which may be used are sodium phenylphosphinate,alumina, silica, and preferably talc.

Other lubricants and mold-release agents are usually used in amounts ofup to 1% by weight. Preference is given to long-chain fatty acids (e.g.stearic acid or behenic acid), salts of these (e.g. calcium stearate orzinc stearate) or montan waxes (mixtures of straight-chain saturatedcarboxylic acids having chain lengths of from 28 to 32 carbon atoms), orcalcium montanate or sodium montanate, or low-molecular-weightpolyethylene waxes or low-molecular-weight polypropylene waxes.

Examples of plasticizers which may be mentioned are dioctyl phthalates,dibenzyl phthalates, butyl benzyl phthalates, hydrocarbon oils andN-(n-butyl)benzene-sulfonamide.

The inventive molding compositions may also comprise from 0 to 2% byweight of fluorine-containing ethylene polymers. These are polymers ofethylene with a fluorine content of from 55 to 76% by weight, preferablyfrom 70 to 76% by weight.

Examples of these are polytetrafluoroethylene (PTFE),tetrafluoroethylene-hexafluoropropylene copolymers andtetrafluoroethylene copolymers with relatively small proportions(generally up to 50% by weight) of copolymerizable ethylenicallyunsaturated monomers. These are described, for example, by Schildknechtin “Vinyl and Related Polymers”, Wiley-Verlag, 1952, pages 484-494 andby Wall in “Fluoropolymers”. (Wiley Interscience, 1972).

These fluorine-containing ethylene polymers have homogeneousdistribution in the molding compositions and preferably have a particlesize d₅₀ (numeric median) in the range from 0.05 to 10 μm, in particularfrom 0.1 to 5 μm. These small particle sizes may particularly preferablybe achieved by the use of aqueous dispersions of fluorine-containingethylene polymers and the incorporation of these into a polyester melt.

The inventive thermoplastic molding compositions may be prepared bymethods known per se, by mixing the starting components in conventionalmixing apparatus, such as screw extruders, Brabender mixers or Banburymixers, and then extruding them. The extrudate may be cooled andcomminuted. It is also possible to premix individual components and thento add the remaining starting materials individually and/or likewise ina mixture. The mixing temperatures are generally from 230 to 290° C.

In another preferred method of operation, components B) and, ifappropriate, C) may be mixed with a polyester prepolymer, compounded,and pelletized. The resultant pellets are then solid-phase-condensed,continuously or batchwise, under an inert gas, at a temperature belowthe melting point of component A) until the desired viscosity has beenreached.

The inventive thermoplastic molding compositions feature goodflowability together with good mechanical properties.

In particular, the processing of the individual components (withoutclumping or caking) is problem-free and possible within short cycletimes, so that a particular application that can be considered isthin-walled components.

These are suitable for the production of fibers, films, and moldings ofany type, in particular for applications as tailgates, switches, housingparts, housing covers, headlamp background (bezel), shower head,fittings, smoothing irons, rotary switches, stove controls, fryer lids,door handles, (rear) mirror housings, (tailgate) screen wipers,sheathing for optical conductors.

EXAMPLES

Component A/1:

Polybutylene terephthalate with a viscosity number VN of 130 ml/g andcarboxy end group content of 34 mval/kg (Ultradur® B 4520 from BASF AG)(VN measured in 0.5% strength by weight solution inphenol/o-dichlorobenzene), 1:1 mixture) at 25° C., comprising 0.65% byweight of pentaerythrityl tetrastearate (component C1, based on 100% byweight of A)

Component A/2:

Polyethylene terephthalate PET with a VN of 74.5 ml/g.

Component A/3:

Polytrimethylene terephthalate with a VN of 106 ml/g.

Component A/4:

Polycarbonate based on bisphenol A and diphenyl carbonate with a VN of59 ml/g.

Component A/5:

PBT with VN 130 ml/g, but without component C1.

Components B:

Mn Mw OH number Acid number Monomers (g/mol) (g/mol) (mg KOH/g) (mgKOH/g) B/1 Adipic acid and 1900 6910 416 31 glycerol B/2 Adipic acid and1730 2580 295 167 glycerol B/3 Adipic acid and 4370 18220 248 93glycerol B/4 Dimethyl 400 1140 273 — terephthalate and glycerol B/5Adipic acid and 2450 12260 213 83 TMP B/6 Adipic acid and 2470 12570 216106 TMP TMP: 1,1,1-Tris(hydroxymethyl)propanePreparation of B/1:

1645 g (11.27 mol) of adipic acid and 868 g (9.43 mol) of glycerolformed an initial charge in a 5 l glass flask which had been equippedwith stirrer, internal thermometer, gas inlet tube, reflux condenser,and vacuum connection with cold trap. 2.5 g of di-n-butyltin oxidecommercially available as Fascat® 4201 were added, and the mixture washeated with the aid of an oil bath to an internal temperature of 140° C.A reduced pressure of 250 mbar was applied in order to remove waterformed during the reaction. The reaction mixture was kept for 4 hours atthe stated temperature and the stated pressure, and then the pressurewas lowered to 100 mbar and the mixture was kept for a further 6 hoursat 140° C. After 8.5 hours, 383 g (4.16 mol) of glycerol were added. Thepressure was then lowered to 20 mbar, and the mixture was kept for afurther 5 hours at 140° C. It was then cooled to room temperature. Thisgave 2409 g of hyperbranched polyester in the form of a clear, viscousliquid. The analytical data are given in Table 1.

Preparation of B/2:

2016 g (13.81 mol) of adipic acid and 1059 g (11.51 mol) of glycerolformed an initial charge in a 5 l glass flask which had been equippedwith stirrer, internal thermometer, gas inlet tube, reflux condenser,and vacuum connection with cold trap. 3.04 g of di-n-butyltin oxidecommercially available as Fascat® 4201 were added, and the mixture washeated with the aid of an oil bath to an internal temperature of 125° C.A reduced pressure of 100 mbar was applied in order to remove waterformed during the reaction. The reaction mixture was kept for 11 hoursat the stated temperature and the stated pressure. It was then cooled toroom temperature. This gave 2645 g of hyperbranched polyester in theform of a clear, viscous liquid. The analytical data are given in Table1.

Preparation of B/3:

2016 g (13.81 mol) of adipic acid and 1059 g (11.51 mol) of glycerolformed an initial charge in a 5 l glass flask which had been equippedwith stirrer, internal thermometer, gas inlet tube, reflux condenser,and vacuum connection with cold trap. 3.04 g of di-n-butyltin oxidecommercially available as Fascat® 4201 were added, and the mixture washeated with the aid of an oil bath to an internal temperature of 150° C.A reduced pressure of 100 mbar was applied in order to remove waterformed during the reaction. The reaction mixture was kept for 9.5 hoursat the stated temperature and the stated pressure. It was then cooled toroom temperature. This gave 2511 g of hyperbranched polyester in theform of a clear, viscous liquid. The analytical data are given in Table1.

Preparation of B/4:

1589 g (8.19 mol) of dimethyl terephthalate and 628 g (6.83 mol) ofglycerol formed an initial charge in a 5 l glass flask which had beenequipped with stirrer, internal thermometer, gas inlet tube, refluxcondenser, and vacuum connection with cold trap. 4.4 g of di-n-butyltinoxide commercially available as Fascat® 4201 were added, and the mixturewas heated with the aid of an oil bath to an internal temperature of140° C. A reduced pressure of 50 mbar was applied in order to removewater formed during the reaction. The reaction mixture was kept for 34hours at the stated temperature and the stated pressure. It was thencooled to room temperature. This gave . . . g of hyperbranched polyesterin the form of a clear, viscous liquid. The analytical data are given inTable 1.

Preparation of B/5:

2000 g (13.70 mol) of adipic acid and 1530 g (11.42 mol) of1,1,1-tris(hydroxymethyl)-propane (TMP) formed an initial charge in a 51 glass flask which had been equipped with stirrer, internalthermometer, gas inlet tube, reflux condenser, and vacuum connectionwith cold trap. 3.53 g of di-n-butyltin oxide commercially available asFascat® 4201 were added, and the mixture was heated with the aid of anoil bath to an internal temperature of 135° C. A reduced pressure of 500mbar was applied in order to remove water formed during the reaction.The reaction mixture was kept for 3.5 hours at the stated temperatureand the stated pressure, and then the pressure was lowered to 300 mbarand the mixture was kept for a further 5.5 hours at 140° C. It was thencooled to room temperature. This gave 3093 g of hyperbranched polyesterin the form of a clear, viscous liquid. The analytical data are given inTable 1.

Preparation of B/6:

2000 g (13.70 mol) of adipic acid and 1530 g (11.42 mol) of TMP formedan initial charge in a 5 l glass flask which had been equipped withstirrer, internal thermometer, gas inlet tube, reflux condenser, andvacuum connection with cold trap. 3.53 g of di-n-butyltin oxidecommercially available as Fascat® 4201 were added, and the mixture washeated with the aid of an oil bath to an internal temperature of 135° C.A reduced pressure of 500 mbar was applied in order to remove waterformed during the reaction. The reaction mixture was kept for 4 hours atthe stated temperature and the stated pressure, and then the pressurewas lowered to 200 mbar and the mixture was kept for a further 5 hoursat 140° C. It was then cooled to room temperature. This gave 3100 g ofhyperbranched polyester in the form of a clear, viscous liquid. Theanalytical data are given in Table 1.

Component B/1c (For Comparison)

Hyperbranched polyester composed of dimethylolpropionic acid accordingto WO 97/45474 with:

Mn 1600 Mw 2100 Tg 40 COOH: 6.1 mg KOH/g OH: 488 mg KOH/g (Boltorn ® H30from Perstorp AB, Sweden)Component C/2:

Chopped glass fibers with an average thickness of 10 μm

Preparation of molding compositions

Components A) to C) were blended in a twin-screw extruder at from 250 to260° C. and extruded into a water bath. After pelletizing and drying,test specimens were injection molded and tested.

MVR was determined to ISO 1133, modulus of elasticity to ISO 527-2,Charpy impact strength to ISO 179-2/1eU, and VN to DIN 53728 or ISO1628.

The inventive compositions and the results of the measurements are foundin the tables.

TABLE 1 Components [% by weight] 1 2 3 4 5 6 A/1 95 65 A/5 95 A/2 95 A/395 A/4 95 B/5 5 5 5 5 5 5 C/2 30 VN 117 117.5 66.4 102.8 60.3 118 MVR171 139 >250 225 160 53.7 Flow spiral 48 48 33 59 21 36 260/80° C. - 2mm (mm)

TABLE 2 7 8 A/1 99 96 B/4 1.00 4.00 VN 105.7 102.8 MVR 97.4 >250 Flowspiral 260/80° C. - 46 92 2 mm (mm) Mechanical properties Stress atmax.: (N/mm) 57.5 51.55 Tensile strain at yield (%) 3.7 2.1 Modulus ofelasticity: (N/mm) 2549 2721 Impact strength - notched 2.3 1.3 (kJ/m²)

TABLE 3 1c 9 10 11 A/1 100 99 98 97 B/1 1 2 3 Analysis VN 119 122 121114 MVR¹ 29.6 26.3 32.8 45.8 Mechanical properties Stress at break 56.256.2 53.7 56.2 (N/mm²) Tensile strain at 3.6 3.6 4.1 3.6 yield (%)Modulus of elasticity 2488 2533 2377 2297 (N/mm²) Notched impact 4.3 4.33.5 4.3 strength (23° C.) (kJ/m²) Flow spiral 35.0 34.4 41.0 47.1260/60° C. 2 mm (cm) ¹MVR at 275°/2.16 kg

TABLE 4 12 13 14 15 16 17 1c A/1 99 97 95 99 97 95 100 B/2 1 3 5 B/3 1 35 Analysis VN 115 115 113 115 116 109 119 Mechanical properties Stressat max.: 56.3 54.5 52.9 55.9 54.5 52.6 56.2 (N/mm) Tensile 23.6 3.8 43.6 3.7 4 3.5 strain at yield (%) Modulus of elasticity 2492 2354 23042469 2410 2326 2488 (N/mm) Impact 88 147 124 144 173 173 199 strength(kJ/m²) Notched 5 5.9 6.1 5.6 5.9 6.1 4.3 impact strength (kJ/m²) Flow42 45 46 42 43 45 35 spiral 260/80° C. − 2 mm (cm)

TABLE 5 Components (% by weight) 1c 2c 3c A/1 99 97 95 B/1c 1.00 3.005.00 VN 125.6 140.5 120.7 MVR 64.2 110 105 DSC GPC Mechanical propertiesStress at max.: (N/mm) Tensile strain at break/yield (%) Modulus ofelasticity (N/mm) Impact strength (−30° C.) (kJ/m²) 156 118 61.5 Impactstrength - notched (kJ/m²) 2.5 2.2 2 Flow spiral 260/80° C. - 2 mm (mm)43 43.5 46.2

1. A thermoplastic molding composition comprising: A) from 10 to 99.99% by weight of at least one thermoplastic polyester; B) from 0.01 to 20% by weight of a hyperbranched A_(x)B_(y) polyester, wherein A_(x) and B_(y) are different monomers and indices x and y are the number of functional groups present in A and B, wherein x is at least 1.1 and y is at least 2.1, wherein B) has an OH number (DIN 53240) of from 0 to 600 mg KOH/g and a COOH number (to DIN 53240) of from 0 to 600 mg KOH/g, wherein B) has a glass transition temperature T_(g) of from −50° C. to 140° C., wherein a degree of branching of B) is from 10 to 99.9%, and wherein B) has both structural and molecular non-uniformity, C) from 0 to 60% by weight of other additives, where the total of the percentages by weight of components A) to C) is 100%.
 2. The thermoplastic molding composition according to claim 1, wherein B) has a number-average molar mass M_(n) of from 300 to 30 000 g/mol.
 3. The thermoplastic molding composition according to claim 1, wherein B) at least has an OH number or a COOH number greater than
 0. 4. The thermoplastic molding composition according to claim 1, wherein B) has an OH number of from 1 to 500 mg KOH/g.
 5. The thermoplastic molding composition according to claim 1, wherein B) has a COOH number of from 1 to 500 mg KOH/g of polyester.
 6. The thermoplastic molding composition according to claim 1, wherein the degree of branching is from 20 to 99%.
 7. The thermoplastic molding composition according to claim 1, wherein the degree of branching is from 20 to 95%.
 8. The thermoplastic molding composition according to claim 1, wherein B) has an M_(n) of from 300 to 30 000 g/mol.
 9. The thermoplastic molding composition according to claim 1, wherein B) has an M_(n) of from 400 to 25 000 g/mol.
 10. The thermoplastic molding composition according to claim 1, wherein the maximum amount of B) is 10% by weight.
 11. The thermoplastic molding composition according to claim 1, wherein B) is obtainable by reacting (a) one or more dicarboxylic acids or one or more derivatives of the same with one or more at least trihydric alcohols or (b) one or more tricarboxylic acids or higher polycarboxylic acids or one or more derivatives of the same with one or more diols if appropriate in the presence of a solvent and optionally in the presence of an acidic inorganic, organometallic, or organic catalyst, or of an enzyme.
 12. The thermoplastic molding composition according to claim 11, where, when variant (a) is utilized, use is made of an at least trihydric alcohol which has hydroxyl groups having at least two different chemical reactivities.
 13. The thermoplastic molding composition according to claim 11, where, when variant (a) is utilized, use is made of an at least trihydric alcohol which has hydroxy groups which all have identical chemical reactivity.
 14. The thermoplastic molding composition according to claim 11, where when variant (b) is utilized an at least trihydric alcohol which has hydroxy groups all of which have identical chemical reactivity is used.
 15. The thermoplastic molding composition according to claim 11, where when variant (b) is utilized an at least one tricarboxylic acid or polycarboxylic acid which has carboxy groups having at least two different reactivities is used.
 16. A method for producing fibers, films, or moldings comprising utilizing the thermoplastic molding composition according to claim
 1. 17. A fiber, a film, or a molding of any type obtainable from the thermoplastic molding compositions according to claim
 1. 